A damaged human heart may be able to repair itself. Medical researchers examined heart transplant patients and found new tissue growing on the heart implant as well as on portions of the old heart.

A team of medical researchers has found evidence in heart transplant patients that new cells grow new muscles and blood vessels on the damaged areas of the heart. Dr. Piero Anversa led the researchers at the New York Medical College. His team found these new cells on the hearts of eight patients who had received heart transplants. They also discovered that these cells resemble stem cells, that is, generic cells, which seem to take the form of heart cells. The researchers also found that the cells come from the patient's body and grow tissue on both the old heart as well as the heart implant.

In fact, Dr. Anversa says the recipient's own cells had rebuilt as much as one-fifth of the donor heart. "We were able to identify that because the (heart transplant) recipients were male and the transplanted hearts were coming from women," he says. "So, by using the (Y) chromosome detection, we were able to distinguish a cell of male origin from a cell of female origin."

Although he has seen these cells accumulate in the heart chambers, Dr. Anversa says he still does not know whether they originate in the heart. "What is becoming rather novel and interesting is that we may have a cell, which possesses the characteristic of stem cells, rushing in the heart," he says.

Dr. Anversa says that if these cells prove to be heart cells, they may be able to transform into any type of heart tissue and repair any part of the human heart. "The next step is to identify and to demonstrate whether there is actually a cardiac stem cell, how powerful this cardiac stem cell is and how much repair we can induce if we understand where these cells are accumulated, whether we can mobilize them and whether we can repair the damaged heart," he says. Dr. Anversa and his colleagues plan to examine whether they can direct these cells to a damaged part of the heart and regenerate it without invasive and risky procedures. "The overall goal is to see whether we can avoid heart transplantation, (whether) we can interfere with the diseased heart and try to repair that diseased heart," he says. The doctor says that the heart repair study may open the door to further medical research on the repair of human organs with the body's own cells. He says that if such treatments prove successful, one day there may not be a need for transplant surgery.